Electrical translating apparatus



J1me 1932- A. .1. SORENSEN ET AL v 1,862,203

ELECTRI CAL TRANS DATING APPARATUS Filed Nov. 1, 1930 f INVENTORSI fi.I'8m =r' sn, H,b0 inf/In WM ATTORNEY.

Patented June 7, 1932.

UNITED STATES PATENT oFsrcE ANDREW J'. SORENSEN, OF PITTSBURGH, AND PHILIP H. BOWLING, 0F SWISSVALE,

PENNSYLVANIA, ASSIGNORS TO THE UN ION- SWITCH & SIGNAL COMPANY, OF SWISS- VALE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA ELECTRICAL T'RANSLATIN'G APPARATUS Application filed November 1, 1930. Serial No. 492,746.

Our invention relates to electrical translating apparatus, and particularly to apparatus comprising an input circuit at times supplied with current, and an output circuit for at times supplying a loadwith current in accordance with current flowing in the input circuit. More particularly our present invention relates to translating apparatus of the type embodying a magnetizable core associated with the input and output circuits and having its permeability varied in accordance with the current in the input circuit to influence the current supplied to the load. Apparatusembodying our invention is particularly suitable for, though in no way limited to, use in automatic train control systems.

We will describe one form of apparatus embodying our invention, and will then point out the novel features thereof in claims.

In the accompanying drawing, Fig. 1 is a diagrammatic view illustrating one form of translating apparatus embodying our invention. Fig. 2 is a detail view showing the physical arrangement of the windings in a portion of the apparatus illustrated in Fig. 1.

Similar reference characters refer to similar parts in both views.

' Referring first to Fig. 1, we have illustrated translating apparatus embodying our invention, and have, in the form here shown, three amplifier stages, the first stage consisting of a single magnetic amplifier A, and the second stage consisting of a single magnetic amplifier B; The third stage comprises two magnetic amplifiers C and -D connected in push-pull relation as will be described hereinafter.

The magnetic amplifiers A, B, C and D are similar and are each constructed as shown in Fig. 2. From this view it will be seen that the amplifier comprises four windings 1, 2, 3 and 4, connected together to form a bridge, across the opposite corners of which alternating current is constantly supplied from a suitable source such as the generator G. These windings are located upon magnetizable cores, as shown in Fig. 2, in which windings 1 and 2 are located upon core 9 and windings 3 and 4 are located upon core 10. Output conductors 13 are connected across the remaining corners of the bridge and may be I .used to supply a load of any suitable type and may feed into the input circuit of a successive amplifier stage of the same type as that here shown. The middle legs of the cores 9 and 10 are provided with input windings 5 and 6, respectively, which windings are connected by means .of conductors 11 in an input circuit which may be supplied with the current which it is desired to amplify. The initial permeabilities of the cores 9 and 10 are adjusted to their optimum values by means of biasing windings 7 and 8 which are connected in series with a suitable source of direct current such as a battery 12. With the parts constructed as shown in Fig. 2, an increase in the current supplied to the input circuit including windings 5 and 6 decreases the permeability of one core and increases the permeability of the other core with the result that the current supplied to the output circuit is varied in one direction. The parts are preferably designed so that this change is in such direction as toincrease the output current. When the current in the input circuit is decreased, the permeability of the two cores are varied in the opposite sense and the output current is decreased. Magnetic ampli'fiers'of the type shown in Fig. 2 and employed in Fig. 1 are disclosed in an application for Letters Patent of the UnitedSta-tes, Serial No. 426,564, filed February 7, 1930, by Andrew J. Sorensen, for electrical translating apparatus.

Reverting now to Fig. 1, the biasingwindings 7 and 8 of each of the four magnetic amplifiers A, B, C and D are connected in series with the battery 12 through a resistor 24 and a reactor 23. Alternating current is supplied to the bridge circuit of each amplifier from generator G. The signal current which it is desired to amplify is applied to the input circuit of the first stage amplifier A. For example, the input circuit of the first stage may be supplied with current in accordance with train control current supplied to the rails for operating a train control system. For this purpose, the rails 15 and 15 are supplied with alternating current from a generator 16 through a contact 17 which is periodically operated, by means formin no part of the present invention, to pro uce periodic variations in the train control current flowing in the track rails. The reference character R designates a receiver comprising. windings Y14 and 1 11 located in inductive relation with the track rails 15 and 15 and connected in series with the primary 18 of a transformer E through a condenser 19 in such manner that the voltages induced in the receiver windings by train'control current in the track rails are additive. The secondary 20 of transformer E is connected across condenser 20, and a portion of this secondary 20 is connected with a full-wave rectifier 21, the output terminals of which supply current to the input windings 5 and 6 of the first stage amplifier A in'parallel with a condenser 22. With this arrangement, it will be seen that the periodically varied signal current in the primary of the transformer E is supplied to theinp-ut circuit of amplifier stage A in the form of impulses of unidirectional current of the same frequency as the frequency of variations in the train control current flowing in the track rails. The transformer E and the associated condenser 20* comprise a filter which prevents the improper operation of the apparatus in response to stray currents not of the frequency of the current delivered by generator 16.

The output circuit of stage A supplies a full-wave rectifier 25, the output terminals of which are connected with'the primary 27 of an interstage transformer F. A condenser 26 is connected across the input terminals of rectifier25. The output from stage A to rectifier 25 is alternating current of the frequency delivered by the generator G modulated in accordance with the input supplied to stage A. The output of rectifier 25 is supplied to primary 27 of transformer F in the form of unidirectional pulses of the frequency of the input supplied to stage A. The secondary 28 of transformer F supplies alternating current, of the frequency of the variations in the current flowing in the track rails, to the input windings 5 and 6 of the second stage amplifier B.

We prefer to construct the amplifier B with unequal numbers of turns in its biasing windings 7 and 8 sothat with no current flowing in the input circuit of this amplifier, a. substantially constant current will be delivered by its output circuit which is connected through a rectifier 29 with the primary 31 of an interstage transformer H. A condenser 30 is connected across the input terminals of rectifier 29. With this arrangement, when the alternating current supplied by secondary 28 of transformer F flows in the input windings5 and 6 of amplifier B, half cycles of one polarity will decrease the output of amplifier B, and half cycles of the same frequency as that supplied to primary 27 of transformer F.

The secondary 32 of transformer H supplies current to the input windings 5 and 6 of amplifier C and also to the input windings 5 and G of amplifier D in series, the connections being so arranged that a given change in the current supplied by secondary 32 of transformer H causes an increase in the current delivered by the output circuit of amplifier C, but causes a decrease in the current delivered by the output circuit of amplifier. D. The output circuit of amplifier C is connected through a rectifier 33 with one winding 37 of a differential relay K, the other winding 38 of which is connected with the output circuit of amplifier D through a rectifier 35. Condensers 34 and 36 are connected across the input terminals of rectifiers 33 and 35, respectively. The alternating current supplied by winding 32 of transformer H is therefore amplified by the push-pull stage comprising amplifiers C and D, and the relay K swings its armature 39 alternately into engagement withvfixed contacts 40 and 41 at the frequency of the variations in the current supplied to the track rails. The pushpuIl amplifier stage comprising amplifiers C and'D is disclosed and claimed in a copending application for Letters Patent of the United States, Serial No. 462,994, filed by Andrew J. Sorensen and Philip H. Dowling, on June 23, 1930, for electrical translating apparatus.

The relay K may be employed to control apparatus on the train which is selectively responsive to the frequency of the operation of this relay in a well known manner. For example, the apparatus here shown may control decoding apparatus including circuits 'which are selectively tuned to electrical resonance at the frequency of the variations in the trackway current, as disclosed and claimed in Letters Patent of the United States No. 1,77 3,472, granted to Paul N. Bos

current through rectifier 21 because the presence of direct current in windings 5 and 6 would be reflected to a very much increased extent in theoutput circuits of the last stage and might seriously interfere with the proper operation of the device. The condensers 26, 80, 34 and 36 have a very important bearing upon the efficiency of the apparatus. These condensers are not used for tuning in the usual sense of the word, and if the values of the condensers are properly chosen the fre quency im ressed upon the in ut circuits of the ampli ers may be varied within wide limits without any great effect upon the am:

plifying power. These condensers also materially improve the efiiciency of the apparatus.

The interstage transformers F and H serve to prevent the supply of the direct current component of the output current of one stage to the input circuit of the next stage. For

example, the output current delivered by stage 1 consists of direct current upon which is impressed an, alternating current of the frequency of variation of the current flowing in the track rails. This direct current component may vary between wide limits in response to variations in the magnitude of the maximum or uninterrupted value of current in the track rails. As the magnitude of this direct current component increases, however, the effic'iency of transformer F decreases, so that the current delivered by secondary 28 of this transformer increases much more slowly than the direct current component of the current. supplied to the primary 27 of transformer F. It may thus be arranged, by

properly proportioning the transformer F and the associated parts, that a comparative- 1y large increase in the maximum value of the current flowing in the rails produces a comparati'vely, small increase in the current in the amplifier, thereby insuring substantially uniform operation of the device K irrespective of variations in the normal value of the current controlled by contact 17.

Although we have herein shown and described only one form of electrical translating apparatus embodying our invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of our invention.

Having thus described our invention, what we claim is:

1. In combination, two magnetic amplifiers each having an input circ uit and an output circuit, means for controlling the ener gization of the input circuit of one said amplifier, a rectifier, a transformer having'its primary connected with the output circuit of i amplifier, a condenser connected across the terminals of said rectifier, and an electro-responsive device receiving energy from the output circuit of said other amplifier.-

3. In combination, two magnetic amplifiers each having an input circuit and an output circuit, means for controlling the energization of the input circuit of one said amplifier, a rectifier, a transformer having its primary connected with the output circuit of said one amplifier through said rectifier, the secondary of said transformer being connected with the input circuit of the other said amplifier, a condenser connected across said rectifier in parallel with the output circuit of said one amplifier, and an electro-responsive device receiving energy from the, output circuit of said other amplifier.

4. In combination, two magnetic amplifiers each having an input circuit and an output circuit, means for controlling the energization of the input circuit of one said amplifier, a rectifier',-a transformer having its former having its primary connected with the output circuit of said other amplifier, and an electro-responsive device receiving energy from the secondary of said second transformer.

5. In combination, a first core carrying two windings, a second core carrying two windings', said four windings being connected in a closed circuit to form a bridge, a load connected across two opposite corners of said bridge, a source of periodic current connected across the other two corners of the bridge, a source of varying input current, an input circuit inductively related with both said cores and including said source of input current and operating in response to a change in the current from said source to produce opposite changes in the permeabilities of said cores, and a condenser connected across said source of input current.

6. In combination with a source of periodically varied alternating signal current, a first magnetic amplifier. means including a rectifier for supplying the input circuit of said first amplifier with unidirectional current periodically varied at the rate of variation of said signal current, a first transformer, means including a rectifier for supplying the primary'of said first transformer with unidirectional current from the output circuit of said first amplifier, a second transformer, a second magnetic amplifier normally supplying a substantially constant current tot e primary of said second transformer, means for causing the electromotive force induced in the secondary of said first transformer to alternately 7 increase and decrease the current supplied by said second amplifier to the primary of the second transformer at the frequency of variation of said signal current, a third and a fourth magnetic amplifier, a differential re- 'lay having two windings receiving energy 1 from the out ut circuit of said third andfourth amplifihrs, and means for supplying energy from the secondary of said second transformer to the input circuits of said third 7 and fourth amplifiers in such manner that a change in said energy causes opposite changes 'in the currents in said two relay windings whereby the relay operates at the frequency of variation of said signal current.

7. In combination with a source of periodically varied alternating signal current, four magnetic amplifiers each having two cores each provided with two windings and having the four windings connected together to form a bridge, output conductors connected with two opposite corners of the bridge of each amplifier, a source of alternating current connected across the remaining corners of each amplifier, an input circuit for each amplifier inductively related with both cores of the associated amplifier and operating in response to a change in the current in such input circuit to cause opposite variations in the per- 3 7' meabilities of such cores, a first condenser, means including a rectifier for supplying curg rent from said-source of signal current to the input circuit of a first one of said amplifiers in parallel with said first condenser, a first transformer having its secondary connected with the input circuit of a second oneof said amplifiers, means including a' rectifier for connecting the primary of said first transformer with the output conductors of said first amplifier, a second transformer-having its secondary connected with the input circuit of the third and fourth amplifiers, means including a rectifier for connecting the primary of said second transformer with the output conductors of said second amplifier, a differential relay having two windings, means including rectifiers for connecting the two windings of said relay with the output conductors of said third and fourth amplifiers respectively, and additional condensers one connected across the output conductors of each said amplifiers. i In testimony whereof we afiix our signatures.

ANDREW J. SORENSENL PHILIP H. DOWLING. 

